I can't re-produce your ratings problem, ratings are working fine for me...
You can delete pics, but not edit them (see notes above). To do this, you have to invoke the "admin" function of your board. By default, this is something like http://www.something.com/cgi-bin/album.pl?function=admin, but if you change "admin" in your album.cfg (*highly recommended*) then you have to change it in the URL as well.
Regarding the CSS, it's all standard, so any CSS changes should work normally. If your background isn't working, I'd make sure you're using the right CSS syntax...
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